Wokring with Workbooks

Create new Workbooks and open existing Workbooks in java shown below:

Create Blank Workbook

Creating blank Microsoft Excel Workbook as shown below

The example below creates a 2003 format XLS and a new format supported from Excel 2007 i.e. XLSX

import java.io.*;
import org.apache.poi.xssf.usermodel.*;
public class workbookexcel {
	public static void main(String[] args) throws Exception {
                // create a old format XLS workbook
		Workbook wb = new HSSFWorkbook();
		FileOutputStream fileOut = new FileOutputStream("c:\poi\workbook.xls");
		wb.write(fileOut);
		fileOut.close();
                // create a XLSX workbook
		Workbook wb = new XSSFWorkbook();
		FileOutputStream fileOut = new FileOutputStream("c:\poi\workbook.xlsx");
		wb.write(fileOut);
		fileOut.close();
	}
}

Save code as workbookexcel.java and  compile and execute it from the command prompt as follows:

$javac workbookexcel.java
$java workbookexcel

If system environments are configured properly with POI library, it will compile ok and execute to generate the blank Excel file workbookexcel.xlsx in C:\poi directory.

How to open an existing workbook

Here is an example code that will open a worksheet we just created. In this example we will use our workbook.xlsx file that we created in our previous example

import java.io.*;
import org.apache.poi.xssf.usermodel.*;
public class workbookopen {
	public static void main(String args[]) throws Exception {
		File xlsx = new File("C:\poi\workbook.xlsx");
		FileInputStream is = new FileInputStream(xlsx);

		XSSFWorkbook workbook = new XSSFWorkbook(is);
		if (xlsx.isFile() && xlsx.exists()) {
			System.out.println("hurray! We've just opened a workbook");
		} else {
			System.out.println("Ahh! there was an error. Please make sure that the file path is correct.");
		}
	}
}

Save  code as workbookopen.java and then compile and execute it from command prompt as shown:

$javac workbookopen.java
$java workbookopen

It will compile and execute to generate the following output.

hurray! We've just opened a workbook

Now that you've opened a workbook, you are able to do all sort of different things with it. You can perform write and read operations. Add rows, cells, forumulas etc.